Service point in out building

[londonfire]

I would use 2 core 25mm swa and a separate 16mm earth. Terminated in a metal clad box (or plastic with 32mm knockouts) feed it from a 100A main switch there to an adaptable box (again with 32mm knockouts. And then supply your board as normal with meter tails from the adaptable box.

Or use 3 core swa and leave one core a bit longer so it will go from the earth at source (tns) to a met at the db. Would look something like this in the end.

 

[Rockingit]

As it's TN-S you don't need to do ^^^. The Cu Equiv. of the armour should more than meet your adiabatic.

 

[Octopus]

I would use 2 core 25mm swa and a separate 16mm earth. Terminated in a metal clad box (or plastic with 32mm knockouts) feed it from a 100A main switch there to an adaptable box (again with 32mm knockouts. And then supply your board as normal with meter tails from the adaptable box.

Or use 3 core swa and leave one core a bit longer so it will go from the earth at source (tns) to a met at the db. Would look something like this in the end.

No overload protection for the sub main then?